The present invention relates to a vehicle power seat, particularly for road vehicles.
Road vehicles are known to be fitted with adjustable seats comprising a seat portion consisting of a carriage hinged at the rear to a reclinable backrest, and mounted on two substantially horizontal lateral guides in such a manner as to slide axially in relation to the vehicle.
The said guides are normally supported on a slide located beneath the seat portion and mounted so as to travel along a further two bottom lateral guides secured to the vehicle floor and sloping upwards towards the front of the vehicle.
On known seats of the aforementioned type, the height of the carriage in relation to the vehicle floor is adjusted by moving the said slide, together with the said carriage, back and forth along the inclined bottom guides; the position of the carriage along the vehicle axis by moving the carriage along the horizontal guides; and the backrest angle in relation to the seat portion by rotating the backrest about the axis of the hinge connecting it to the carriage.
On known seats of the aforementioned type, both carriage movements are usually controlled by means of two rack-and-pinion couplings controlled by respective electric motors located either centrally in relation to the said guides and underneath the carriage, or outside the said guides. In the latter case, to prevent jamming of the carriage or slide along the furthermost guides from the motors, both the carriage and slide present complex drive and/or strengthening members extending underneath the carriage.
Regardless of location, the said motors are invariably cumbersome, and cannot be employed on seat portions featuring bucket type cushions, the springing of which requires the formation of a center cavity on the carriage; which cavity rules out any possibility of using either centrally-located motors underneath the carriage, or centrally-located drive and/or strengthening members in the case of laterally-located motors.
Consequently, known power seats of the aforementioned type all present relatively high-section cushions, due to the need for employing flat-based carriages, whereas bucket cushions are employed excusively on manually-adjusted seats. What is more, in addition to being cumbersome, the motors employed on known power seats are invariably expensive, and difficult to assemble and service.